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Bone Densitometry Services for Research Investigators
Bone Densitometry Services provides more than 20 years of expertise in the design and implementation of Bone Densitometry Research protocols for both human and animal research. Whether you are implementing an industry sponsored clinical trial, or, designing your own study, our unit is specifically designed to acquire and analyze all types of bone densitometry scans.
Although the majority of sponsored clinical research trials have a Bone Densitometry Protocol provided by either the trial sponsor or provided by the Bone Density Quality Assurance Center, many investigators have self-designed studies. For those studies falling outside of industry sponsored trials, we offer the service of designing methods for bone densitometry research protocols involving animal as well as human participants, and coordinate the performance of the measurements.
In addition, we have bone density quality assurance standards to insure that the data received is of the highest value.
ABOUT OUR BONE DENSITOMETRY RESEARCH UNIT
We are located at the Oregon Health & Science University in the Hatfield Research Building. The space is designed specifically for research services. Our Bone Densitometry technicians are Oregon State licensed and trained in all areas of both human and animal research.
ABOUT OUR DENSITOMETRY EQUIPMENT AND HOW IT WORKS
HOLOGIC QDR 4500W - DUAL ENERGY X-RAY ABSORPTIOMETRY (DEXA)
The basic principle of DXA data acquisition is based on the different bone and soft tissue attenuation characteristics at two-pulsed X-ray levels. A calibration drum, comprised of known amounts of bone and soft tissue equivalent materials is placed in the beam. As the beam passes through the patient (or animal), more lower energy X-rays than higher energy X-rays are absorbed by the anatomical structures. The beam is then registered by the detectors in the C-arm. The raw scan data, containing the attenuation values of tissue, bone, and the calibration drum are captured and transferred to a computer. An algorithm interprets each pixel, creates an image and quantitative measurement of the bone and body tissues.
The choice of site may be important because of differences in the proportions of trabecular and cortical bone. Some conditions, such as steroid induced bone loss1, affect predominantly trabecular bone, and may therefore be detected first at the lumbar spine. Others diseases, such as growth hormone deficiency, seem to cause greater deficits in cortical bone and may best be detected by scanning the whole body or forearm.
Scan sites available2
The spine consists of a number of vertebrae categorized as cervical (upper column), thoracic (mid column), lumbar (mid to lower column), and sacrum and coccyx (at the end). Significant bone loss due to aging or osteoporosis is often observed in the vertebrae, and particularly in the lumbar area.The AP Lumbar Spine is the most widely used anatomical site for the evaluation of osteoporosis. The vertebral bodies, L1 through L4, contain approximately 40% cortical, and 60% trabecular bone. The high amount of trabecular bone and the relative ease of reproducibility of position of the spine provide an important source for baseline bone density data. We also have the ability to provide bone density results for a Scoliotic Spine.
Lateral Spine Scan
Supine Lateral Spine bone mineral density (BMD) enables clinicians to obtain a reliable, quantitative BMD measurement of trabecular-rich vertebral bodies in the supine position, while avoiding artifacts (e.g., degenerative joint disease) that often affects the posterior elements or anterior ligaments. By moving the detector C-arm and not the patient, supine lateral measurements have demonstrated superior precision (1%) over quantitative measurements in the decubitus position (>3%). BMD measurements of the spine in the AP projection include both cortical and trabecular bone. Trabecular bone makes up 80-90% of vertebral bodies and is more metabolically active than cortical bone. It is the first bone tissue lost with the onset of bone disease or replaced with the initiation of therapy. By confining measurement to the vertebral bodies in the lateral projection, supine lateral DXA provides the most sensitive means of detecting bone loss or gain.
Low Density Spine
Low Density Spine option is available for patients with very low bone density.
The femur is the skeletal site where the most serious consequences of osteoporosis (fractures) often occur. Bone Mineral Density (BMD) results for the proximal femur (Hip) scans are reported for five different anatomical areas: Total Hip, Femoral Neck, Trochanter, Inter-Trochanter, and Ward's Triangle.
- The Total Hip is the most reproducible measurement of the hip and has become the preferred clinical measurement of the hip bone mineral density.
- The Femoral Neck region contains both cortical and trabecular bone and provides an easily reproducible area in the hip for DXA scanning. The analysis is completed by placing a specific region at the anatomical landmark. That landmark, called the "greater trochanter notch" permits reproducibility for longitudinal scanning.
- The Trochanter is a triangular region rich in trabecular bone whose boundaries are the lateral edge of the femur and the inferior edge of the neck box and the solid line where the edge of the femur changes curvature below the trochanter.
- The Inter-Trochanteric region is below the Femoral Neck.
- The Ward's Triangle is a small box approximately 1cm x 1cm at the area of minimum density in the femoral neck region.
Prosthetic HipProsthetic Hip option provides the ability to scan and analyze prosthetic hips, as well as other anatomical sites that may include metal. Changes in bone mass surrounding metal implants can be assessed by using the specially designed algorithm. The metal components of the implant are removed from the bone mass measurement.
Bone loss may be notable in the forearm. The forearm scan includes the region of the radius and ulna and the wrist bones (carpals).
This software allows regional and global measurements of the Whole Body. An advanced application of QDR technology can directly measure fat and skeletal mass and is useful in research and clinical studies. The technique is non-invasive and allows regional or total body measurements and estimates of appendicular muscle mass.
The anatomical areas analyzed are:
- the head
- the left arm
- the right arm
- the left rib
- the right rib
- the thoracic spine
- the lateral spine
- the pelvis
- the left leg
- the right leg
The subregions analyzed include all of the above except the head.
Body Composition Analysis
Body Composition Analysis option provides the ability to analyze the soft tissue composition of the entire body and to follow the changes in soft tissue composition over time in response to intervention such as diet and exercise. Analysis of fat mass and lean mass can be reported for the entire body and head, arms, trunk, pelvis and legs.
High Power Whole Body (A)
High Power Whole Body option improves measurement accuracy on severely obese subjects during acquisition and analysis of whole body scans.
Infant Whole Body (A)
Infant Whole Body option allows the acquisition, display and analysis of infants.
Pediatric Whole Body
Pediatric Whole Body provides whole body bone density results, as well as, body composition. This is available for patients weighing 18 pounds or more.
Decubitus Lateral option allows the acquisition, display and analysis of scans of the lateral view of the spine.
Instant Vertebral Assessment and Quantitative Morphometry
Instant Vertebral Assessment (IVA) allows the acquisition of scans that allow the determining of the presence or absence of vertebral fractures. The Quantitative Morphometry option analyzes the shape of vertebra using vertebral height measurements and calculations of those heights to compute wedge ratios. The anatomical sites that are viewed are the lateral vertebral bodies from T4 to L4.
Small Animal option provides the ability to perform two types of small animal measurements:
- Whole body bone mineral and body composition measurements in rats. This software is optimized for adult rats weighing between 200 and 750 grams.
- Bone Mineral Content (BMC) and Bone Mineral Density (BMD) measurements of small animal bones using regional high resolution. The regional high resolution software is optimized for excised rat femurs and spines but may also be used to measure these bones in vivo.
General Region of Interest
General Region of Interest option, which is sometimes referred to as subregions, provides the ability to use a nonstandard region of interest to analyze a scan. This feature is available for spine, hip and forearm scan types but not for supine lateral scans
In addition to the routine scans listed above, we can design very specific protocols for scanning and analyzing both whole body and specific sites for mice, rats, pigs, primates, etc. We can also design protocols for analyzing excised bones of mice, rats, pigs, primates, cadaver, etc.
Costs of Bone Densitometry
Bone densitometry for both industry and non-industry (NIH, NSF, etc.) sponsored research is available. Research rates are available.
Radiation Use and Safety
All protocols must have approval from Radiation Use and Safety.
For information on costs please contact Catherine Wilson-Skogen at (503) 494-4814 or email her.
(Dexa images courtesy of Hologic, Inc)
1. Bianchi ML. Glucocorticoids and bone: some general remarks and some special observations in pediatric patients. Calcif Tissue Int 2002;70:384-90
2. Hologic QDR® for Windows XP® Reference Manual ®Copyright 2000-2004, Hologic Inc.